A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

W. Kasparek, M.I. Petelin, D.Yu. Shchegolkov, V. Erckmann, B. Plaum, A. Bruschi

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A fast directional switch (FADIS) is described, which allows controlled switching of high-power microwaves between two outputs. A possible application could be synchronous stabilization of neoclassical tearing modes (NTMs). Generally, the device can be used to share the installed EC power between different types of launchers or different applications (e.g. in ITER, midplane/upper launcher). The switching is performed electronically without moving parts by a small frequency-shift keying of the gyrotron (some tens of megahertz), and a narrow-band diplexer. The device can be operated as a beam combiner also, which offers attractive transmission perspectives in multi-megawatt ECRH systems. In addition, these diplexers are useful for plasma diagnostic systems employing high-power sources due to their filter characteristics. The principle and the design of a four-port quasi-optical resonator diplexer is presented. Low-power measurements of switching contrast, mode purity and efficiency show good agreement with theory. Preliminary frequency modulation characteristics of gyrotrons are shown, and first results from high-power switching experiments using the ECRH system for W7-X are presented. © 2008 IAEA, Vienna.
Original languageEnglish
Article number054010
Pages (from-to)-
JournalNuclear Fusion
Issue number5
Publication statusPublished - 1 May 2008
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Kasparek, W., Petelin, M. I., Shchegolkov, D. Y., Erckmann, V., Plaum, B., & Bruschi, A. (2008). A fast switch, combiner and narrow-band filter for high-power millimetre wave beams. Nuclear Fusion, 48(5), -. [054010]. https://doi.org/10.1088/0029-5515/48/5/054010